Problem: $ { {3} \times \left[\begin{array}{rrr}{1} & {-1} & {1} \\ {0} & {2} & {-2}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{3}\times{1} & {3}\times{-1} & {3}\times{1} \\ {3}\times{0} & {3}\times{2} & {3}\times{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{3} & {-3} & {3} \\ {0} & {6} & {-6}\end{array}\right]}$